/S. I. Smith on American Crustacea. 131 



GelasimiTs brevifrons stimpson. 



Annals Lyceum Nat. Hist, New York, vol. vii, p. 229, 1860. 



Of this species, which was found in a lagoon at Todos Santos, near 

 Cape St. Lucas, Lower California, I have seen only a single, female 

 specimen, which was kindly loaned from the collection of the Chicago 

 Academy by Dr. Stimpson. 



As far as can be judged from the female alone, it is very distinct 

 from any other species with which I am acquainted and seems to be 

 most closely allied to G. minax. It differs from the female of Q. m,i- 

 nax, in having the carapax broader in proportion and not nearly so 

 much narrowed behind, and the dorsal surface less convex ; the cari- 

 nae of the lateral margins ai'e more prominent and, from the form of 

 the carapax, are not so much curved ; the front is shorter and more 

 perpendicular, and the anterior margin of the orbital border is more 

 convex, leaving a broader space between it and the posterior margin ; 

 and finally, the meral segments of the ambulatory legs are much nar- 

 rower in proportion, and are marked with conspicuous, transverse pli- 

 cations. 



Length of carapax, 17"5"""; breadth of carapax, 25'0"'"^; ratio of 

 length to breadth, 1 : 1*43. 



Gelasimus pngnax, sp. nov. 



Gelasimus vocans {pars) Gould, Report on the Invertebrata of Massichusetts, p. 325, 

 1841 ; G. vocans, var. A, DeKay, Natural History of New York, Crust., p. 14, pi. 6, 

 fig. 10, 1844 (raore Cancer vocans Linne). 



Gelasimus pugilator LeConte, loc. cit., p. 403 {non Bosc). 



(?) Gelasimus palusfris {pars) Stimpson, Annals Lyceum Nat. Hist., New York, p. 62, 

 1859 {non Edwards). 



Plate II, figure 1, Plate IV, figure 2-2''. 



Male. The carapax is quite similar to that of G. minax but it is 

 broader, the dorsal surface is smooth and there are no tubercles on 

 the branchial regions, the front is narrower and projects farther down- 

 ward, the anterolateral angle is sharp and the anterior part of the 

 lateral margin is not at all, or only very slightly, arcuate. 



In the larger cheliped, the anterior surface of the merus is usually 

 somewhat granular or finely tuberculose, especially along the inferior 

 border, its outline is triangular and much broader toward the carpus 

 than in G. m,inax, and the distal portion of the superior margin is 

 high and arcuate and not tuberculated as in that species. The superior 

 surface of the carpus is covered with small, rounded tubercles and the 

 inner surface is crossed by an oblique, and more or less tuberculated, 



